A semi-analytical modelling of cutting using crystal plasticity theory and flow line approach

Abstract

A semi-analytical model for orthogonal cutting taking into account microstructure evolution and its influence on the chip formation process is developed for polycrystalline materials. To describe the 2D material flow in the chip, a thermomechanical crystal plasticity constitutive model was combined with the flow line approach. The microstructure evolution, as well as material flow stress and temperature rise, are obtained through a Visco-Plastic Self-Consistent (VPSC) mean field crystal plasticity model combined with a Mechanical Threshold Stress (MTS) physical-based hardening law. The proposed approach allows capturing in a relative simple way the variations of thermomechanical fields such as stress, strain, strain rate and temperature in the primary shear zone. The model validation is conducted by successful comparisons with experimental results of Shi and Liu [63] in terms of cutting forces and chip thickness during orthogonal cutting of a HY 100 steel alloy. The predicted results indicate that equivalent strain and temperature increase from the chip free surface to the tool tip. In contrast, the equivalent stress exhibits a reverse trend.